Conventionally known fuel injection valves for an internal combustion engine have been provided with nozzle holes whose hole axes form a predetermined angle with a plane perpendicular to a central axis of a valve body. This type of fuel injection valve is disclosed, for example, in Japanese Patent Application Laid-Open No. HEI 7-127550. Based on this art wherein a fuel jet adjusting plate has nozzle holes of which all the hole axes form a predetermined angle with the plane perpendicular to the central axis the nozzle holes may be arranged along two circles or more coaxial with the central axis.
FIG. 16 is a partial plan view of a conventional fuel injection valve for an internal combustion engine, illustrating the fuel jet adjusting plate where, based on the aforementioned art, the nozzle holes are arranged along two circles coaxial with the central axis. Referring to FIG. 16, reference characters H1′ to H12′ denote nozzle holes, C1′ a first circle coaxial with the valve body and along which the nozzle holes H1′ to H8′ are arranged. C2′ a second circle coaxial with the valve body and along which the nozzle holes H9′ to H12′ are arranged, and L0′ the central axis. The second circle C2′ has a diameter smaller than that of the first circle C1′. FIG. 17 is a sectional view taken along line XVII—XVII in FIG. 16. In FIG. 17, a plane perpendicular to the central axis L0′ is defined as a reference plane SB′. A cross section shown in FIG. 17 consists of a plane S0′ perpendicular to the reference plane SB′ and including the central axis L0′, a plane S10′ perpendicular to the reference plane SB′ and including a hole axis L10′ of the nozzle hole H10′, and a plane S3′ perpendicular to the reference plane SB′ and including a hole axis L3′ of the nozzle hole H3′. Referring to FIG. 17, reference characters F10′, F3′ denote fuel sprays injected through the nozzle holes H10′, H3′ respectively. The hole axis L3′ forms an acute angle a3′ with the reference plane SB′, and the hole axis L10′ forms an acute angle a10′ with the reference plane SB′. As can be seen from FIG. 17, the acute angle a3′ is equal to the acute angle a10′. Although not shown, hole axes L1′ to L12′ form acute angles a1′ to a12′ respectively, with the reference plane SB′ and all these acute angles a1′ to a12′ assume an equal value.
As illustrated in FIG. 17, however, the fuel sprays F3′, F10′ injected through the nozzle holes H3′, H10′ are diffused and thus interfere with each other. In this case, the fuel sprays F3′, F10′ become unstable, which makes it impossible to suitably atomize injected fuel.